Trash detention means between a roadway and a surface drain to close the passage of trash and to pass water at a slow rate, and to open to pass water at a faster rate, while then also permitting passage of solid trash.
Roadways must frequently be provided at low spots with drains to carry away surface water. These drains are horizontal openings, usually rectangular, which open into drainage systems. Generally they open into a catch basin that in turn enters into the drainage system that conveys the stream to a distant place.
These drains customarily are covered by a grating such as a grating of steel rods or bars that allow flow of water through openings between them. The problem with these arrangements is that, while water can readily be drained, solid trash can also pass through. Then it enters the catch basin where it must be cleaned out so the system does not plug up and potentially flood the area.
Still, the grating must be available to pass water at all times, and also to support vehicles and people at all times. What is lacking is a selective system which will support people, vehicles and trash and permit slow flow of water during relatively dry times, while excluding trash from the system so it can be picked up by surface means such as a sweeper when the flow is slow or zero. At times of heavy flow, it must open to permit the more rapid flow of water, accompanied by some residual trash that has not been swept up, while still supporting vehicles and people. It is an object of this invention to provide such a system.
Apparatus according to this invention is intended to be installed in a roadway surface drain. Such a drain will ordinarily be horizontal, and be placed at a low point in the roadway or shoulder. A grating is fitted in an opening into the drain with strength sufficient to support vehicles or persons expected to run or stand on it. It is an open grating with openings between its rods or bars to pass water through it. It is anticipated that solid trash, as well as water, will reach this grating.
Immediately beneath the grating is a pivoted closure plate, which when closed will permit slow flow of water past it while preventing passage of solid trash. This enables the trash to be swept up before it can enter the drainage system.
An actuator is provided which is linked to the closure plate in such a way as to open the closure plate to permit flow of water at a sufficiently high rate, but remains closed to trash in slow rates (or no flow), while still passing the water at the slow rate.
According to a feature of the invention, a counterweight linkage system holds the closure plate closed until a collector receives enough water to overcome the counterweight. A sufficient rate of flow will keep the closure open while the rate of flow remains sufficiently high.